You can mitigate the issue by reducing the pot value or putting a resistor between pins 2&3 on the pot to change the curve to a more aani-log shape. That's something I need to play with soon to figure out what values. Had the same issue building a tube VH4 amp

i don't know if this is allowed here but i've ordered a small batch of weasel v84 and now have 4 boards left.I'm located in germany and would give them away for production cost + shipping (for germany/austria roughly ~5€ for one or ~7€ for two).Sadly packaging + shipping costs are higher than the actual prodcution cost which is <2€.

If anyone is interested I'll calc the exact price (it's a bit less than stated, i was just too lazy to calculate it exactly).

I tracked down the issues. I built two - one with a 12V reg and one powered direct from a 9V battery.The one with the 12V reg had a jack issue - not making ground properly which caused oscillation.The 9V powered re-less one - the battery voltage was too low, about 7.5V. Sent the circuit into oscillation.

Comparing the sound of 9V pedal to the 12V pedal, the 9V one has a little muddiness in comparison, lack of headroom I suppose. Not a huge amount but it's enough to want to make me want to power it from more volts...

Thanks for the PCBs Bajaaman! Now to do some recording and see how it compares to my tube VH4

In the tone stack, the schematics show a Fender style tone stack with the mid pot wired as a rheostat. In the real amp the tone stack is Marshall style with the mid pot wired as a pot. The values are the same, but this change changes the tone shaping a lot! Much more bass and less treble with the Fender stack.

Can someone check the real pedal to confirm whether it is on fact fender style or Marshall style? It's an easy wiring reconfiguration to make and the PCB wont change.

I checked the photo and the tone stack does appear to be wired Fender style. So the schematic is correct. I wonder why they went that way instead of like the real amp... I think i'll try the other configuration anyway to see how it sounds

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As an Information for others that may encounter issues similar to mine (massive feedback when gain is turned up "too far").I was able to suppress the feedback by increasing the feedback cap on the 3rd gain stage (IC2A, the one with the 1N5232 Z-Diodes) a LOT! I opted for a quick trial & error with i had flying around here and had to go up to 560pf to eliminate feedback on full gain.

Could it be the caused by different Z-Diode capacitance (afaik they do have some capacitance, right?) ?!

It's nice to have a working Pedal now, but I hate not understanding the why on issues like this one .